There's no way to activate Cloud9 products right now, because they should have signed with a new ecommerce provider after Esellerate closed in 2019, but since the former Cloud9 owners have quit the flight sim business years ago, they surely haven't done that.
We have been trying to get hold of former Cloud9 owners, to ask permission to do something about, like automatically activating everything with no key, but haven't got any reply so far.